In electrical systems for controlling an entrance gate and/or a garage door of a dwelling, it is typical to locate the various units which make up the system where it is necessary and connect them through electric wires.
In a dwelling, the following, for example, may be installed: a motor for one wing of the gate, a motor for the other wing of the gate, a motor for the garage door, a radio receiver for receiving requests for movement of the gate and of the door coming from remote control transmitters, key-operated selectors and/or command keypads for operating the gate or the door, various safety photocell systems (each photocell system is composed of a receiver and a transmitter), and luminous and/or acoustic devices for signalling the movement of the gate and the door.
Until a short time ago, the number of devices installed was fairly small (four or five) and these devices, for the sake of simplicity, were located very close to each other, for example next to the gate.
Recently, international safety regulations, on the one hand, and the requirements of users, on the other hand, have resulted in a considerable increase in the number of devices installed (often ten or so or even more) and in the impossibility of locating them close to each other; this tendency will continue in the future.
The specific sector of doors and gates for garages for commercial and industrial premises is governed at a European level by CEN standard prEN 13241.
Installed devices of this kind are electrically connected to the electrical control system; more precisely, generally these devices are connected directly and locally to the peripheral units of the electrical control system, which units are connected directly, by means of electric wires, to the central unit of the electrical control system, the “heart” of the system.
In these systems, therefore, many electric wires are required.
Just because of the type of application, there are many such electric wires and they are often very long (various tens of meters and, in some case, even hundreds of meters) and therefore their cost is generally fairly high; moreover, the cost of installing them (usually underground, preferably inside protective pipes) must be taken into consideration.
Again, because of the type of application, these electric wires are positioned outdoors, underground and sparsely (since there are substantially no spatial constraints), and therefore, the risk of cutting one of them, for example when working in a garden, is quite possible.
Moreover, the plurality of electric wires associated with different installed devices results in a complex electrical system and easily gives rise, during installation, to errors in connection (both with regard to the polarity of the wires and with regard to the correspondence between wires and connectors) even on the part of qualified personnel.
A solution to the abovementioned problems, which is of interest from a practical point of view, must be simple (both in terms of the connections and in terms of apparatus), relatively inexpensive and must not require either specialized knowledge or particular skill on the part of the personnel responsible for installation of the system.